What is the diagnostic approach for lymphedema?

Diagnostic Approach for Lymphedema

The diagnosis of lymphedema should be based on a combination of clinical assessment of limb volume/circumference changes, with diagnostic criteria including volume increase ≥10% or circumference increase ≥2 cm compared to the unaffected limb, and can be confirmed with specialized imaging when necessary. 1

Clinical Assessment

History and Risk Factors

• Identify history of:
  • Cancer treatment (especially breast cancer, with radiation to lymph nodes) 2, 1
  • Lymph node removal (5+ nodes significantly increases risk) 1
  • Radiation therapy (particularly to supraclavicular, axillary, and internal mammary regions) 1
  • Recurrent infections in the affected area 1
  • Trauma to the affected limb 3
  • Obesity (significant risk factor) 1

Physical Examination

• Assess for characteristic signs:
  • Swelling of affected limb/area 4
  • Peau d'orange appearance (orange peel-like skin texture) 1
  • Pitting or non-pitting edema 2
  • Fibrosis and tissue quality changes 2
  • Skin changes (thickening, hyperkeratosis) 1
  • Limited range of motion in affected limb 5

Objective Measurements

Circumferential Measurements

• Circumferential measurement should be used to diagnose upper extremity lymphedema (Stage 1 or greater) 2
• Diagnostic criteria: circumference increase ≥2 cm compared to unaffected limb 1
• For hand lymphedema: figure-of-8 method for assessment 2
• For head and neck lymphedema: measurement at single point under jawline 2

Volume Measurements

• Water displacement: diagnostic with >200 mL difference or >10% interlimb difference 2
• Calculated volume differential ≥200 ml helps rule in lymphedema 2
• If preoperative measures available: 5% or greater volume change from baseline above and below the elbow is diagnostic 2
• Volume ratio of 1.04 may indicate upper extremity lymphedema 2

Advanced Diagnostic Tools

Bioimpedance Analysis

• Should be used to detect lymphatic transport impairments and diagnose subclinical/early stage lymphedema (Stage 0 and 1) 2
• L-Dex score >7.1 is diagnostic when no preoperative assessment is available 2
• L-Dex score >10 above preoperative baseline is diagnostic 2
• Note: In moderate to late stage lymphedema with fibrosis, BIA results may show decreased extracellular fluid despite increased tissue volume 2

Imaging Studies

• Lymphoscintigraphy: Gold standard to detect lymphatic system impairment 2, 6
• Ultrasound: Should be used as a diagnostic tool to identify tissue changes 2
• MRI: May be used as a diagnostic tool 2
• CT: May be used as a diagnostic tool 2
• Lymphography: May be used to detect lymphatic system impairment 2

Not Recommended as Diagnostic Tools

• Perometry (useful for assessment but not diagnosis) 2
• Tissue Dielectric Constant (for assessment only) 2
• Dual-energy X-Ray Absorptiometry (for assessment only) 2
• Tonometry (not recommended) 2

Patient-Reported Symptoms

• Self-reported swelling, heaviness, and numbness should be investigated to facilitate early diagnosis 2
• Validated questionnaires that assist in diagnosis:
  • Norman Questionnaire 2
  • Morbidity Screening Tool 2

Staging and Classification

Once diagnosed, lymphedema should be staged:

• Stage 0: Subclinical (no visible swelling but impaired lymphatic transport)
• Stage 1: Reversible edema (pitting, subsides with elevation)
• Stage 2: Spontaneously irreversible edema (fibrosis begins)
• Stage 3: Lymphostatic elephantiasis (severe fibrosis, skin changes) 3

When to Refer

• Patients with clinical symptoms or swelling suggestive of lymphedema should be referred to a therapist knowledgeable about lymphedema diagnosis and treatment (physical therapist, occupational therapist, or lymphedema specialist) 2
• Referral to specialized lymphedema therapist is essential for optimal management 1

Common Pitfalls

• Misdiagnosing lymphedema as generic swelling or edema from other causes 4
• Failing to obtain baseline measurements before cancer treatment, which complicates later diagnosis 2
• Overlooking early, subclinical lymphedema when intervention would be most effective 1
• Not distinguishing between primary (congenital) and secondary (acquired) lymphedema, which may affect treatment approach 6, 7
• Neglecting to assess for complications like cellulitis/erysipelas, which require immediate antibiotic treatment 1, 5

By following this diagnostic approach, clinicians can accurately identify lymphedema and initiate appropriate management to prevent progression and complications that impact morbidity, mortality, and quality of life.